Numerous types of pressure sensitive adhesive tapes capable of connecting or joining two surfaces (e.g., adhering a sheet of paper onto a tabletop) are well known. For example, #810 Scotch™ Magic™ brand transparent tape, manufactured by Minnesota Mining and Manufacturing Company, St. Paul, Minn. is readily available from numerous retail outlets. Such pressure sensitive adhesive tapes, including #810 Scotch™ Magic™ brand transparent tape, are generally available as a continuous roll of tape capable of being conveniently dispensed from any of a number of manually-operated roll-type tape dispensers, such as those disclosed in U.S. Pat. No. 4,928,864 and D116,599, having a cutting edge located on the dispenser for cutting the tape into strips of the desired length. While effective for quickly and efficiently dispensing most pressure sensitive adhesive tapes, it is difficult to create tape strips of uniform length due to the natural variations in the length of tape unwound from the roll of adhesive tape between cuttings. Hence, such dispensers are not suitable for those situations requiring the quick and efficient dispensing of uniform lengths of pressure sensitive adhesive tape.
It is also known to dispense pressure sensitive adhesive tape, such as Scotch™ Magic™ brand transparent tape, from a stacked pad of tape strips. Such pads of adhesive tape strips are disclosed in U.S. Pat. Nos. 4,650,706 and 4,895,746. Both patents disclose stacked pads of adhesive tape strips wherein a first end portion of each individual strip is treated so as to provide a nonadhesive end tab ('706) or an area of reduced adhesion to an adjacent tape strip ('746) at a first end of the pad. The nonadhesive end tab or area of reduced adhesion facilitates initial separation of the first end of an uppermost tape strip from the first end of an immediately underlying tape strip, allowing the uppermost tape strip to be peeled off the pad. While generally effective for dispensing uniform lengths of pressure sensitive adhesive tape, such pads are somewhat cumbersome to use and are not well suited for use in those situations where only one hand is available for dispensing the tape, such as gift wrapping.
Post-it® brand notes and Post-it® brand flags, available from Minnesota Mining and Manufacturing Company of St. Paul, Minn., require a coating of releasable pressure sensitive adhesive only along one end of the substrate, and can therefore be conveniently dispensed from a container by alternating the adhesive end of each sheet/flag in the stack between opposed first and second ends of the stack (e.g., forming a Z-stack of sheets). Such a stack of Post-it® brand flags and associated shuttling dispenser is disclosed in U.S. Pat. No. 4,770,320. Similarly, a pad of W-stacked sheets and associated dispensers are disclosed in U.S. Pat. Nos. 4,416,392, 4,562,938, 4,586,629, and 4,653,666. This alternating style of stacking the sheets/flags is effective because the sheets/flags are adhesively bonded together with a relatively weak repositionable pressure sensitive adhesive on only one end of the sheet/flag. Such sheets are not suitable for joining or connecting surfaces together because of the relatively small percentages of such sheets coated with adhesive and the relatively weak nature of the pressure sensitive adhesive used with such sheets/flags.
A significant advance in the construction and dispensing of pads of adhesive tape strips is disclosed in U.S. Pat. No. 5,401,547. '547 discloses a pad of superimposed adhesive tape strips wherein the adhesive layer of each tape strip is releasably adhered to an adjacent tape strip at a first adhesion level at a first end and a second adhesion level at a second end (i.e., differential release), and sequential tape strips are longitudinally reversed so as to align the first end of each tape strip with the second end of an immediately overlaying and an immediately underlying tape strip. A preferred manner of achieving such differential release disclosed by '547 is to coat the entire surface area of a first major surface of each strip with a pressure sensitive adhesive and coat the second end portion of the second major surface of each tape strip with a low adhesion backsize. Such an alternately stacked pad of differential release tape strips can be conveniently dispensed from an associated dispenser with a single hand while maintaining a continuous coating of an aggressive pressure sensitive adhesive on the substrate.
While constituting a significant improvement, the pads disclosed by '547 must comply with narrow quality control standards in order to achieve the sliding action required between adjacent tape strips for proper dispensing while preventing fanning of the stacked strips (i.e., preventing the tape strips from accidentally and unintentionally sliding relative to one another before each strip is dispensed). Furthermore, as described in Blackwell et al., when the necessary differential release requirement is achieved by the application of a premium low adhesion backsize on one end of the tape strips and a basic adhesion backsize on the other end, that portion of the tape strip coated with the premium low adhesion backsize does not consistently maintain any written indicia.
WO00/29224 discloses a technique for dispensing a pad of adhesive tape strips which maintains the convenience of one hand dispensing realized with the pads of adhesive tape strips and dispensing technique disclosed by '547 without requiring the pad to adhere to the stringent differential release limitations required by the '547 pads. Briefly, the novel technique involves dispensing each tape strip at a peel angle of less than 45° between the tape strip being dispensed (i.e., the overlying tape strip) and the next tape strip (i.e., the intermediate tape strip) prior to complete separation of the overlying tape strip from the intermediate tape strip and prior to release of a longitudinal end of the intermediate tape strip from the tape strip immediately underneath the intermediate tape strip (i.e., the underlying tape strip).
Unfortunately, the tape pads, tape dispensers and dispensing techniques taught by '547 and WO00/29224 for the dispensing of pressure sensitive adhesive tape strips are not well suited for dispensing larger oversized sheets of pressure sensitive adhesive tape, such as those used as a protective cover over mailing labels, due to the high peel force required to dispense such oversized pressure sensitive adhesive tape sheets and a tendency for the sheets to double over and adhere to itself during dispensing.
Accordingly, a substantial need exists for a pad of adhesive tape sheets, a dispenser for a pad of adhesive tape sheets and/or a dispensing technique capable of easily and reliably dispensing sheets of pressure sensitive adhesive tape with the same convenience provided by the pads, dispensers and dispensing techniques disclosed by '547 and WO00/29224 for the dispensing of pressure sensitive adhesive tape strips.